Blinded by the Lies or Lifting the Blinds? Using Signal Detection Theory to Examine Correlates of Belief in Plausible vs. Implausible Conspiracy Theories

Based on signal detection theory, this study provides and tests a framework which considers the possibility that conspiracies do happen and can be plausible, while simultaneously accounting for the problematic epistemic aspects of belief in implausible conspiracy theories. For that purpose, both the ability to accurately distinguish between plausible and implausible conspiracy theories (discernment) as well as the overall inclination to regard conspiracy theories as credible regardless of their plausibility (response bias) are examined. Employing two large scale, preregistered online surveys in Germany and the UK, the credibility judgments about 16 conspiracy theories (eight plausible, eight implausible) were analyzed. Results showed that news media knowledge structures and actively open-minded thinking were consistently associated with participants’ discernment. Conspiracy mentality, in turn, was a key determinant of participants’ response bias. The framework presented clarifies why rational and irrational elements of conspiracy belief ought to be distinguished - as differences in belief content also relate to differences in citizens information processing capabilities.Key words: conspiracy theories, plausibility, signal detection theory